Methods The optometer is composed of singlechip, handle and LCD.The eyesight is examined by selecting exposure of random sample eye-chart mark E within direction keys on the handle.

采用微计算控制视力检测仪，其由单片、手柄和液晶显示构成，手柄具有下左右方向等功能键，根据手柄的按键选取出现视标"E"朝向的正确与否来检测视力。